Isoflurane alleviates the inflammatory response in endotoxin-induced acute lung injury (ALI). In this study, we investigated the protective mechanism of isoflurane postconditioning in lipopolysaccharide (LPS)-induced ALI. Exposure to isoflurane decreased miR-155 and upregulated HIF-1 alpha and HO-1 mRNA and protein. The effects of isoflurane on HIF-1 alpha mRNA and protein could be inhibited by overexpression of miR-155. Furthermore, mice overexpressing miR-155 had higher levels of TNF-alpha and IL-1 beta in BALF when exposed to isoflurane after LPS challenge. Conversely, downregulation of miR-155 promoted isoflurane effects on HIF-1 alpha expression. These results suggest that isoflurane posttreatment at 1 MAC for 4 hour alleviates LPS-induced ALI and cell injury by triggering miR-155-HIF-1 alpha pathway, leading to upregulation of HO-1.